Light-emitting device and electronic apparatus including the same

ABSTRACT

Provided is a light-emitting device including: a first electrode; a second electrode facing the first electrode; and an interlayer between the first electrode and the second electrode and including an emission layer. The emission layer includes: a first emission layer including a first host; and a second emission layer including a second host, wherein a triplet energy (T1 H1 ) of the first host and a triplet energy (T1 H2 ) of the second host satisfy Equation (1): 
         T 1 H1   −T 1 H2 ≥0.2 eV  (1).

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2020-0090568, filed on Jul. 21, 2020, in the Korean Intellectual Property Office, the entire content of which is hereby incorporated by reference.

BACKGROUND 1. Field

One or more embodiments of the present disclosure relate to a light-emitting device and an electronic apparatus including the same.

2. Description of Related Art

Light-emitting devices are self-emission devices that have wide viewing angles, high contrast ratios, short response times, and excellent characteristics in terms of brightness, driving voltage, and response speed, compared to other devices in the art.

In a light-emitting device, a first electrode is placed on a substrate, and a hole transport region, an emission layer, an electron transport region, and a second electrode are sequentially arranged on the first electrode. Holes provided from the first electrode may move toward the emission layer through the hole transport region, and electrons provided from the second electrode may move toward the emission layer through the electron transport region. Carriers, such as holes and electrons, recombine in the emission layer to produce excitons, thereby generating light.

SUMMARY

One or more embodiments of the present disclosure include a device and/or the like that improves a lifespan compared to another device of the related art by prevents or reduces deterioration of an electron blocking layer.

Additional aspects of embodiments will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure.

According to one or more embodiments, a light-emitting device includes:

a first electrode,

a second electrode facing the first electrode,

an interlayer between the first electrode and the second electrode and including an emission layer,

the emission layer including: a first emission layer including a first host; and

a second emission layer including a second host,

wherein a triplet energy (T1_(H1)) of the first host and a triplet energy (T1_(H2)) of the second host satisfy Equation (1):

T1_(H1) −T1_(H2)≥0.2 eV  (1).

According to one or more embodiments, an electronic apparatus includes:

the light-emitting device.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic view of a light-emitting device according to an embodiment of the present disclosure;

FIG. 2 is a cross-sectional view showing a light-emitting apparatus according to an embodiment of the present disclosure; and

FIG. 3 is a cross-sectional view showing a light-emitting apparatus according to another embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in more detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of embodiments of the present description. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Throughout the disclosure, the expression “at least one of a, b or c” indicates only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof.

An emission layer that emits fluorescent blue light of an organic light-emitting device in the related art includes a single host and a single dopant, and such a host has stronger electron transport (ET) characteristics than hole transport (HT) characteristics. For this reason, holes and electrons recombine at an interface between an electron blocking layer and an emission layer, thereby generating triplet-triplet fusion (TTF). Accordingly, deterioration or degradation of the electron blocking layer occurs, resulting in a shorted lifespan of a device having such an arrangement.

An aspect of embodiments of the present disclosure provides a light-emitting device including:

a first electrode;

a second electrode facing the first electrode; and

an interlayer between the first electrode and the second electrode and including an emission layer,

the emission layer including a first emission layer including a first host and a second emission layer including a second host,

wherein a triplet energy (T1_(H1)) of the first host and a triplet energy (T1_(H2)) of the second host satisfy Equation (1):

T1_(H1) −T1_(H2)≥0.2 eV  (1).

In the light-emitting device according to an embodiment of the present disclosure, a recombination region of holes and electrons is moved to an interface between the first emission layer and the second emission layer, rather than being at an interface between an electron blocking layer and an emission layer.

Accordingly, deterioration or degradation of an electron blocking layer due to generated excitons may be prevented or reduced.

In the light-emitting device according to another embodiment of the present disclosure, the first emission layer has a relatively higher T1 energy level than the second emission layer. Thus, TTF occurs at the side of the second emission layer (e.g., TTF occurs at an interface between the first emission layer and the second emission layer), and the TTF area is narrow. For example, a region in which TTF occurs is relatively small and, in some embodiments, occurs at the interface between the first emission layer and the second emission layer and a region of the second emission layer adjacent to the interface between the first emission layer and the second emission layer. Accordingly, luminescence efficiency of the light-emitting may be improved.

When a difference between a triplet energy (T1_(H1)) of the first host and a triplet energy (T1_(H2)) of the second host is less than 0.2 eV, the area where TTF occurs is relatively widely distributed compared to a case where the difference is equal to or greater than 0.2 eV. Thus, when the difference is equal to or greater than 0.2 eV, there may be a problem that fails to contribute to the improvement of efficiency of the device.

In an embodiment, in the light-emitting device, the first electrode may be an anode, the second electrode may include a cathode, and the interlayer may further include a hole transport region between the first electrode and the emission layer and an electron transport region between the emission layer and the second electrode,

wherein the hole transport region may include a hole injection layer, a hole transport layer, a emission auxiliary layer, an electron blocking layer or any combination thereof, and the electron transport region may include a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

In an embodiment, each of the first emission layer and the second emission layer in the light-emitting device may include a dopant, wherein the dopant of the first emission layer and the dopant of the second emission layer may be the same compounds.

In an embodiment, the first emission layer and the second emission layer in the light-emitting device may be in contact (e.g., physical contact) with each other.

In an embodiment, the emission layer of the light-emitting device may emit blue light.

In an embodiment, the emission layer of the light-emitting device may be a fluorescent emission layer.

In an embodiment, the interlayer of the light-emitting device may further include a hole transport layer and an electron blocking layer that are between the first electrode and the emission layer, and the first emission layer may be in direct contact (e.g., physical contact) with the electron blocking layer. For example, the interlayer may further include a hole injection layer, and the hole injection layer may be in contact (e.g., physical contact) with the first electrode. For example, the hole injection layer may include a charge-generating material. For example, the hole injection layer may include a p-dopant compound.

In an embodiment, the interlayer of the light-emitting device may further include an electron transport layer and a hole blocking layer that are between the second electrode and the emission layer, and the second emission layer may be in direct contact (e.g., physical contact) with the hole blocking layer.

For example, the electron transport layer may include a metal-containing material. The metal-containing material will be described below.

In an embodiment, in the light-emitting device, the first electrode may be an anode, the second electrode may be a cathode, and the first emission layer and the second emission layer may be in contact (e.g., physical contact) with each other.

Here, holes provided from the first electrode and electrons provided from the second electrode may recombine at an interface between the first emission layer and the second emission layer.

For example, the first emission layer may be located in the direction of the first electrode.

The hole and the electron recombine to generate TTF and emit light. Here, an area where the recombination occurs is at an interface between the first emission layer and the second emission layer, so that deterioration or degradation of an electron blocking layer that occurs in an light-emitting device of the related art does not occur (or substantially does not occur) in embodiments of the present disclosure. In this regard, a lifespan of a device may be significantly improved.

In the light-emitting device according to an embodiment of the present disclosure, the triplet energy relationship between the first host and the second host satisfies (or only needs to satisfy) Equation (1):

T1_(H1) −T1_(H2)≥0.2 eV  (1).

In an embodiment, the first host may be a pyrene derivative compound. For example, the first host may be a symmetrical pyrene derivative compound. For example, the first host may be a pyrene derivative compound in which two secondary amine groups are substituted with pyrene.

In an embodiment, the first host may be any one of the following compounds:

In an embodiment, the second host may be an anthracene derivative compound. For example, the second host may be an anthracene derivative compound in which one aryl group and one heteroaryl group are substituted with anthracene. For example, the second host may be an asymmetrical compound.

In an embodiment, the second host may be any one of the following compounds.

In an embodiment, the light-emitting device may further include a capping layer. The capping layer will be further described below.

Another aspect of embodiments of the present disclosure includes an electronic apparatus including the light-emitting device.

In an embodiment, the electronic apparatus may further include a thin-film transistor,

wherein the thin-film transistor may include a source electrode and a drain electrode, and

the first electrode of the light-emitting device may be electrically coupled with one of the source electrode and the drain electrode of the thin-film transistor.

In an embodiment, the electronic apparatus may further include quantum dots.

The term “interlayer,” as used herein, refers to a single layer and/or all of a plurality of layers between a first electrode and a second electrode of a light-emitting device.

Description of FIG. 1

FIG. 1 is a schematic cross-sectional view of a light-emitting device 10 according to an embodiment. The light-emitting device 10 includes a first electrode 110, an interlayer 130, and a second electrode 150.

Hereinafter, the structure of the light-emitting device 10 according to an embodiment and a method of manufacturing the light-emitting device 10 will be described in connection with FIG. 1.

First Electrode 110

In FIG. 1, a substrate may be additionally under the first electrode 110 or above the second electrode 150. The substrate may be a glass substrate and/or a plastic substrate. The substrate may be a flexible substrate. In one or more embodiments, the substrate may include plastics having excellent heat resistance and durability, such as polyimide, polyethylene terephthalate (PET), polycarbonate, polyethylene naphthalate, polyarylate (PAR), polyetherimide, or any combination thereof.

The first electrode 110 may be formed by, for example, depositing and/or sputtering a material for forming the first electrode 110 on the substrate. When the first electrode 110 is an anode, a high work function material that can easily inject holes may be used as the material for forming the first electrode 110.

The first electrode 110 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. In an embodiment, when the first electrode 110 is a transmissive electrode, the material for forming the first electrode 110 may include indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO₂), zinc oxide (ZnO), or any combination thereof. In one or more embodiments, when the first electrode 110 is a semi-transmissive electrode or a reflective electrode, the material for forming the first electrode 110 may include magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), or any combination thereof.

The first electrode 110 may have a single-layered structure including (e.g., consisting of) a single layer or a multi-layered structure including a plurality of layers. For example, the first electrode 110 may have a three-layered structure of ITO/Ag/ITO.

Interlayer 130

The interlayer 130 is on the first electrode 110. The interlayer 130 includes an emission layer.

The interlayer 130 may further include a hole transport region between the first electrode 110 and the emission layer and an electron transport region between the emission layer and the second electrode 150.

The interlayer 130 may further include metal-containing compounds such as organometallic compounds, inorganic materials such as quantum dots, and/or the like, in addition to various suitable organic materials.

In an embodiment, the interlayer 130 may include, i) two or more emitting units sequentially stacked between the first electrode 110 and the second electrode 150 and ii) a charge generation layer between the two emitting units. When the interlayer 130 includes the emitting unit and the charge generation layer as described above, the light-emitting device 10 may be a tandem light-emitting device.

Hole Transport Region in Interlayer 130

The hole transport region may have: i) a single-layered structure including (e.g., consisting of) a single layer including (e.g., consisting of) a single material, ii) a single-layered structure including (e.g., consisting of) a single layer including (e.g., consisting of) a plurality of different materials, or iii) a multi-layered structure including a plurality of layers including different materials.

The hole transport region may include a hole injection layer, a hole transport layer, an emission auxiliary layer, an electron blocking layer, or any combination thereof.

For example, the hole transport region may have a multi-layered structure including a hole injection layer/hole transport layer structure, a hole injection layer/hole transport layer/emission auxiliary layer structure, a hole injection layer/emission auxiliary layer structure, a hole transport layer/emission auxiliary layer structure, or a hole injection layer/hole transport layer/electron blocking layer structure, wherein, in each structure, layers are stacked sequentially on the first electrode 110.

The hole transport region may include a compound represented by Formula 201, a compound represented by Formula 202, or any combination thereof:

wherein, in Formulae 201 and 202,

L₂₀₁ to L₂₀₄ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a),

L₂₀₅ may be *—O—*′, *—N(Q₂₀₁)-*′, a C₁-C₂₀ alkylene group unsubstituted or substituted with at least one R_(10a), a C₂-C₂₀ alkenylene group unsubstituted or substituted with at least one R_(10a), a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a), or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a),

xa1 to xa4 may each independently be an integer from 0 to 5,

xa5 may be an integer from 1 to 10,

R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a),

R₂₀₁ and R₂₀₂ may optionally be linked to each other via a single bond, a C₁-C₅ alkylene group unsubstituted or substituted with at least one R_(10a), or a C₂-C₅ alkenylene group unsubstituted or substituted with at least one R_(10a), to form a C₈-C₆₀ polycyclic group unsubstituted or substituted with at least one R_(10a) (for example, a carbazole group and/or the like) (for example, see Compound HT16),

R₂₀₃ and R₂₀₄ may optionally be linked to each other via a single bond, a C₁-C₅ alkylene group unsubstituted or substituted with at least one R_(10a), or a C₂-C₅ alkenylene group unsubstituted or substituted with at least one R_(10a), to form a C₈-C₆₀ polycyclic group unsubstituted or substituted with at least one R_(10a), and

na1 may be an integer from 1 to 4.

For example, Formulae 201 and 202 may each include at least one of groups represented by Formulae CY201 to CY217:

In Formulae CY201 to CY217, R_(10b) and R_(10c) may each be the same as described in connection with R_(10a), ring CY201 to ring CY204 may each independently be a C₃-C₂₀ carbocyclic group or a C₁-C₂₀ heterocyclic group, and at least one hydrogen in Formula CY201 to CY217 may be unsubstituted or substituted with at least one R_(10a).

In an embodiment, ring CY201 to ring CY204 in Formulae CY201 to CY217 may each independently be a benzene group, a naphthalene group, a phenanthrene group, or an anthracene group.

In one or more embodiments, Formulae 201 and 202 may each include at least one selected from the groups represented by Formulae CY201 to CY203.

In one or more embodiments, Formula 201 may include at least one selected from the groups represented by Formulae CY201 to CY203 and at least one selected from the groups represented by Formulae CY204 to CY217.

In one or more embodiments, in Formula 201, xa1 may be is 1, R₂₀₁ may be the group represented by one of Formulae CY201 to CY203, xa2 may be 0, and R₂₀₂ may be the group represented by one of Formulae CY204 to CY207.

In one or more embodiments, each of Formulae 201 and 202 may not include the group represented by one of Formulae CY201 to CY203.

In one or more embodiments, each of Formulae 201 and 202 may not include the group represented by one of Formulae CY201 to CY203, but may include at least one of the groups represented by Formulae CY204 to CY217.

In one or more embodiments, each of one of Formulae 201 and 202 may not include the group represented by one of Formulae CY201 to CY217.

For example, the hole transport region may include one of Compounds HT1 to HT44, m-MTDATA, TDATA, 2-TNATA, NPB(NPD), β-NPB, TPD, Spiro-TPD, Spiro-NPB, methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), or any combination thereof:

A thickness of the hole transport region may be in a range of about 50 Å to about 10,000 Å, for example, about 100 Å to about 4,000 Å. When the hole transport region includes the hole injection layer, the hole transport layer, or any combination thereof, a thickness of the hole injection layer may be in a range of about 100 Å to about 9,000 Å, for example, about 100 Å to about 1,000 Å, and a thickness of the hole transport layer may be in a range of about 50 Å to about 2,000 Å, for example, about 100 Å to about 1,500 Å. When the thicknesses of the hole transport region, the hole injection layer, and the hole transport layer are within any of the ranges above, suitable or satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.

The emission auxiliary layer may increase light-emission efficiency by compensating for an optical resonance distance according to the wavelength of light emitted by the emission layer, and the electron blocking layer may block or reduce the flow of electrons from the electron transport region. The emission auxiliary layer and the electron blocking layer may include the materials as described above.

P-Dopant

The hole transport region may further include, in addition to these materials, a charge-generating material for the improvement of conductive properties (e.g., electrically conductive properties). The charge-generating material may be uniformly or non-uniformly dispersed in the hole transport region (for example, in the form of a single layer of a charge-generating material).

The charge-generating material may be, for example, a p-dopant.

For example, the p-dopant may have a lowest unoccupied molecular orbital (LUMO) energy level of equal to or less than −3.5 eV.

In an embodiment, the p-dopant may include a quinone derivative, a cyano group-containing compound, a compound containing element EL1 and element EL2, or any combination thereof.

Examples of the quinone derivative include TCNQ and F4-TCNQ.

Examples of the cyano group-containing compound include HAT-CN and a compound represented by Formula 221.

wherein, in Formula 221,

R₂₂₁ to R₂₂₃ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a), and

at least one of R₂₂₁ to R₂₂₃ may each independently be a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group, each substituted with: a cyano group; —F; —Cl; —Br; —I; a C₁-C₂₀ alkyl group substituted with a cyano group, —F, —Cl, —Br, —I, or any combination thereof; or any combination thereof.

Regarding the compound containing element EL1 and element EL2, element EL1 may be a metal, a metalloid, or a combination thereof, and element EL2 may be a non-metal, a metalloid, or a combination thereof.

Examples of the metal include: an alkali metal (for example, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and/or the like); alkaline earth metal (for example, beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and/or the like); transition metal (for example, titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), and/or the like); post-transition metals (for example, zinc (Zn), indium (In), tin (Sn), and/or the like); and lanthanide metal (for example, lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), ruthenium (Lu), and/or the like).

Examples of the metalloid include silicon (Si), antimony (Sb), and tellurium (Te).

Examples of the non-metal include oxygen (O) and halogen (for example, F, Cl, Br, I, etc.).

In an embodiment, examples of the compound containing element EL1 and element EL2 metal oxide, metal halide (for example, metal fluoride, metal chloride, metal bromide, and/or metal iodide), metalloid halide (for example, metalloid fluoride, metalloid chloride, metalloid bromide, and/or metalloid iodide), metal telluride, and any combination thereof.

Examples of the metal oxide include tungsten oxide (for example, WO, W₂O₃, WO₂, WO₃, and/or W₂O₅), vanadium oxide (for example, VO, V₂O₃, VO₂, and/or V₂O₅), molybdenum oxide (MoO, Mo₂O₃, MoO₂, MoO₃, and/or Mo₂O₅), and rhenium oxide (for example, ReO₃).

Examples of the metal halide include alkali metal halide, alkaline earth metal halide, transition metal halide, post-transition metal halide, and lanthanide metal halide.

Examples of the alkali metal halide include LiF, NaF, KF, RbF, CsF, LiCl, NaCl, KCl, RbCl, CsCl, LiBr, NaBr, KBr, RbBr, CsBr, LiI, NaI, KI, RbI, and CsI.

Examples of the alkaline earth metal halide include BeF₂, MgF₂, CaF₂, SrF₂, BaF₂, BeCl₂, MgCl₂, CaCl₂, SrCl₂, BaCl₂, BeBr₂, MgBr₂, CaBr₂, SrBr₂, BaBr₂, BeI₂, MgI₂, CaI₂, SrI₂, and BaI₂.

Examples of the transition metal halide include titanium halide (for example, TiF₄, TiCl₄, TiBr₄, and/or TiI₄), zirconium halide (for example, ZrF₄, ZrCl₄, ZrBr₄, and/or ZrI₄), hafnium halide (for example, HfF₄, HfCl₄, HfBr₄, or HfI₄), vanadium halide (for example, VF₃, VCl₃, VBr₃, and/or V₁₃), niobium halide (for example, NbF₃, NbCl₃, NbBr₃, and/or NbI₃), tantalum halide (for example, TaF₃, TaCl₃, TaBr₃, and/or TaI₃), chromium halide (for example, CrF₃, CrCl₃, CrBr₃, and/or CrI₃), molybdenum halide (for example, MoF₃, MoCl₃, MoBr₃, and/or MoI₃), tungsten halide (for example, WF₃, WCl₃, WBr₃, and/or WI₃), manganese halide (for example, MnF₂, MnCl₂, MnBr₂, and/or MnI₂), technetium halide (for example, TcF₂, TcCl₂, TcBr₂, and/or TcI₂), rhenium halide (for example, ReF₂, ReCl₂, ReBr₂, and/or ReI₂), iron halide (for example, FeF₂, FeCl₂, FeBr₂, and/or FeI₂), ruthenium halide (for example, RuF₂, RuC₁₂, RuBr₂, and/or RuI₂), osmium halide (for example, OsF₂, OsC₁₂, OsBr₂, and/or OsI₂), cobalt halide (for example, CoF₂, CoCl₂, CoBr₂, and/or Col₂), rhodium halide (for example, RhF₂, RhCl₂, RhBr₂, and/or RhI₂), iridium halide (for example, IrF₂, IrCl₂, IrBr₂, and/or IrI₂), nickel halide (for example, NiF₂, NiCl₂, NiBr₂, and/or NiI₂), palladium halide (for example, PdF₂, PdCl₂, PdBr₂, and/or PdI₂), platinum halide (for example, PtF₂, PtCl₂, PtBr₂, and/or PtI₂), copper halide (for example, CuF, CuCl, CuBr, and/or CuI), silver halide (for example, AgF, AgCl, AgBr, and/or AgI), and gold halide (for example, AuF, AuCl, AuBr, and/or AuI).

Examples of the post-transition metal halide include zinc halide (for example, ZnF₂, ZnCl₂, ZnBr₂, and/or ZnI₂), indium halide (for example, InI₃), and tin halide (for example, SnI₂).

Examples of the lanthanide metal halide include YbF, YbF₂, YbF₃, SmF₃, YbCl, YbCl₂, YbCl₃ SmCl₃, YbBr, YbBr₂, YbBr₃ SmBr₃, YbI, YbI₂, YbI₃, and SmI₃.

Examples of the metalloid halide include antimony halide (for example, SbCl₅).

Examples of the metal telluride include an alkali metal telluride (for example, Li₂Te, Na₂Te, K₂Te, Rb₂Te, and/or Cs₂Te), alkaline earth metal telluride (for example, BeTe, MgTe, CaTe, SrTe, and/or BaTe), transition metal telluride (for example, TiTe₂, ZrTe₂, HfTe₂, V₂Te₃, Nb₂Te₃, Ta₂Te₃, Cr₂Te₃, Mo₂Te₃, W₂Te₃, MnTe, TcTe, ReTe, FeTe, RuTe, OsTe, CoTe, RhTe, IrTe, NiTe, PdTe, PtTe, Cu₂Te, CuTe, Ag₂Te, AgTe, and/or Au₂Te), post-transition metal telluride (for example, ZnTe), and lanthanide metal telluride (for example, LaTe, CeTe, PrTe, NdTe, PmTe, EuTe, GdTe, TbTe, DyTe, HoTe, ErTe, TmTe, YbTe, and/or LuTe).

Emission Layer in Interlayer 130

When the light-emitting device 10 is a full-color light-emitting device, the emission layer may be patterned into a red emission layer, a green emission layer, and/or a blue emission layer, according to a sub-pixel. In an embodiment, the emission layer may have a stacked structure of two or more layers of a red emission layer, a green emission layer, and a blue emission layer, in which the two or more layers contact (e.g., physically contact) each other or are separated from each other. In one or more embodiments, the emission layer may include two or more materials of a red light-emitting material, a green light-emitting material, and a blue light-emitting material, in which the two or more materials are mixed with each other in a single layer to emit white light.

The emission layer may include a host and a dopant. The dopant may include a phosphorescent dopant, a fluorescent dopant, or any combination thereof.

An amount of the dopant in the emission layer may be in a range of about 0.01 parts by weight to about 15 parts by weight based on 100 parts by weight of the host.

In one or more embodiments, the emission layer may include a delayed fluorescence material. The delayed fluorescence material may act as a host or a dopant in the emission layer.

A thickness of the emission layer may be in a range of about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å. When the thickness of the emission layer is within any of the ranges above, excellent light-emission characteristics may be obtained without a substantial increase in driving voltage.

Host in Emission Layer

The triplet energy (T1_(H1)) of the first host and the triplet energy (T1_(H2)) of the second host that are included in the first emission layer and the second emission layer may satisfy Equation (1):

T1_(H1) −T1_(H2)≥0.2 eV  (1).

In the light-emitting device according to an embodiment of the present disclosure, the triplet energy relationship between the first host and the second host only needs to satisfy Equation (1). For example, any suitable first host and any suitable second host that satisfy Equation (1) may be used.

In an embodiment, the first host may be a pyrene derivative compound. In one or more embodiments, the first host may be a symmetrical pyrene derivative compound. In one or more embodiments, the first host may be a pyrene derivative compound in which two secondary amine groups are substituted with pyrene.

In an embodiment, the second host may be an anthracene derivative compound. In one or more embodiments, the second host may be an anthracene derivative compound in which one aryl group and one heteroaryl group are substituted with anthracene. In one or more embodiments, the second host may be an asymmetrical compound.

Examples of the first host and the second host may be the same as described above.

Additional examples of the first host and the second host may include as follows:

Fluorescent Dopant

The fluorescent dopant may include an amine group-containing compound, a styryl group-containing compound, or any combination thereof.

In an embodiment, the fluorescent dopant may include a compound represented by Formula 501:

wherein, in Formula 501,

Ar₅₀₁, L₅₀₁ to L₅₀₃, R₅₀₁, and R₅₀₂ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a),

xd1 to xd3 may each independently be 0, 1, 2, or 3, and

xd4 may be 1, 2, 3, 4, 5, or 6.

In an embodiment, Ar₅₀₁ in Formula 501 may be a condensed cyclic group (for example, an anthracene group, a chrysene group, or a pyrene group) in which three or more monocyclic groups are condensed.

In one or more embodiments xd4 in Formula 501 may be 2.

In one or more embodiments, the fluorescent dopant may include: one of Compounds FD1 to FD36; DPVBi; DPAVBi; or any combination thereof:

Delayed Fluorescence Material

The emission layer may include a delayed fluorescence material.

The delayed fluorescence material as used herein may be selected from any suitable compound that is capable of emitting delayed fluorescent light based on a delayed fluorescent emission mechanism.

The delayed fluorescence material included in the emission layer may act as a host or a dopant depending on the type (e.g., composition) of other materials included in the emission layer.

In an embodiment, a difference between a triplet energy level (eV) of the delayed fluorescence material and a singlet energy level (eV) of the delayed fluorescence material may be equal to or greater than 0 eV and equal to or less than 0.5 eV. When the difference between the triplet energy level (eV) of the delayed fluorescence material and the singlet energy level (eV) of the delayed fluorescence material satisfies the ranges above, up-conversion from the triplet state to the singlet state of the delayed fluorescence materials may effectively occur, and thus, the light-emitting device 10 may have improved luminescence efficiency.

For example, the delayed fluorescence material may include i) a material that includes at least one electron donor (for example, a π electron-rich C₃-C₆₀ cyclic group, such as a carbazole group) and at least one electron acceptor (for example, a sulfoxide group, a cyano group, or a π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group), ii) a material including a C₈-C₆₀ polycyclic group in which two or more cyclic groups share boron (B) and are condensed with each other (e.g., combined together with each other).

The delayed fluorescence material may include at least one of Compounds DF1 to DF9:

Quantum Dot

The quantum dot as used herein refers to the crystal of a semiconductor compound, and may include any suitable material that is capable of emitting light of various suitable emission wavelengths depending on the size of the crystal.

A diameter of the quantum dot may be, for example, in a range of about 1 nm to about 10 nm.

The quantum dot may be synthesized by a wet chemical process, an organometallic chemical vapor deposition process, a molecular beam epitaxy process, and/or a process that is similar to these processes.

The wet chemical process refers to a method in which an organic solvent and a precursor material are mixed, and then, a quantum dot particle crystal is grown. When the crystal grows, the organic solvent acts as a dispersant naturally coordinated on the surface of the quantum dot crystal and controls the growth of the crystal. Accordingly, by using a process that is easily performed at low costs compared to a vapor deposition process, such as a metal organic chemical vapor deposition (MOCVD) process and a molecular beam epitaxy (MBE) process, the growth of quantum dot particles may be controlled.

The quantum dot may include a Group III-VI semiconductor compound, a Group II-VI semiconductor compound, a Group III-V semiconductor compound, a Group III-VI semiconductor compound, a Group I-III-VI semiconductor compound, a Group IV-VI semiconductor compound, a Group IV element or compound, or any combination thereof.

Examples of the Group III-VI semiconductor compound include a binary compound, such as In₂S₃; a ternary compound, such as AgInS, AgInS₂, CuInS, and/or CuInS₂; or any combination thereof.

Examples of the Group II-VI semiconductor compound include a binary compound, such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, and/or MgS; a ternary compound, such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, and/or MgZnS; a quaternary compound, such as CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and/or HgZnSTe; and any combination thereof.

Examples of the Group III-V semiconductor compound include a binary compound, such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, and/or InSb; a ternary compound, such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InAlP, InNAs, InNSb, InPAs, InPSb, and/or GaAlNP; a quaternary compound, such as GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and/or InAlPSb; and any combination thereof. The Group III-V semiconductor compound may further include a Group II element. Examples of the Group III-V semiconductor compound further including a Group II element include InZnP, InGaZnP, and InAlZnP.

Examples of the Group III-VI semiconductor compound include a binary compound, such as GaS, GaSe, Ga₂Se₃, GaTe, InS, InSe, In₂Se₃, and/or InTe; a ternary compound, such as InGaS₃, and/or InGaSe₃; and any combination thereof.

Examples of the Group semiconductor compound include a ternary compound, such as AgInS, AgInS₂, CuInS, CuInS₂, CuGaO₂, AgGaO₂, and/or AgAlO₂; and any combination thereof.

Examples of the Group IV-VI semiconductor compound include a binary compound, such as SnS, SnSe, SnTe, PbS, PbSe, and/or PbTe; a ternary compound, such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, and/or SnPbTe; a quaternary compound, such as SnPbSSe, SnPbSeTe, and/or SnPbSTe; and any combination thereof.

In an embodiment, the Group IV element or compound may include a single element compound, such as Si or Ge; a binary compound, such as SiC and/or SiGe; or any combination thereof.

Each element included in the multi-element compound such as the binary compound, a ternary compound, and a quaternary compound may be present in a particle at a uniform concentration or a non-uniform concentration.

In some embodiments, the quantum dot may have a single structure having a uniform (e.g., substantially uniform) concentration of each element included in the corresponding quantum dot or a dual structure of a core-shell. In an embodiment, the material included in the core may be different from the material included in the shell.

The shell of the quantum dot may function as a protective layer for maintaining semiconductor characteristics by preventing or reducing chemical degeneration of the core and/or may function as a charging layer for imparting electrophoretic characteristics to the quantum dot. The shell may be a single layer or a multilayer. An interface between the core and the shell may have a concentration gradient in which the concentration of elements existing in the shell decreases along a direction toward the center of the core.

Examples of the shell of the quantum dot include a metal and/or non-metal oxide, a semiconductor compound, or any combination thereof. Examples of the oxide of the metal or non-metal include a binary compound, such as SiO₂, Al₂O₃, TiO₂, ZnO, MnO, Mn₂O₃, Mn₃O₄, CuO, FeO, Fe₂O₃, Fe₃O₄, CoO, Co₃O₄, and/or NiO; a ternary compound, such as MgAl₂O₄, CoFe₂O₄, NiFe₂O₄, and/or CoMn₂O₄; and any combination thereof. Examples of the semiconductor compound include, as described herein, the Group III-VI semiconductor compounds, the Group II-VI semiconductor compounds, the Group III-V semiconductor compounds, the Group III-VI semiconductor compounds, the Group semiconductor compounds, the Group IV-VI semiconductor compounds, or any combination thereof. In an embodiment, the semiconductor compound may include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, or any combination thereof.

A full width at half maximum (FWHM) of an emission wavelength spectrum of the quantum dot may be equal to or less than about 45 nm, for example, equal to or less than about 40 nm, and for example, equal to or less than about 30 nm. When the FWHM of the emission wavelength spectrum of the quantum dot is within any of the ranges above, color purity or color reproduction may be improved. In addition, light emitted through such quantum dots is irradiated in omnidirection (e.g., substantially every direction). Accordingly, a wide viewing angle may be increased.

In addition, the quantum dot may be, for example, a spherical, pyramidal, multi-arm, and/or cubic nanoparticle, a nanotube, a nanowire, a nanofiber, and/or nanoplate particle.

By adjusting the size of the quantum dots, the energy band gap may also be adjusted, thereby obtaining light of various suitable wavelengths in the quantum dot emission layer. Therefore, by using quantum dots of different sizes, a light-emitting device that emits light of various suitable wavelengths may be implemented. In an embodiment, the size of the quantum dots may be selected to emit red, green, and/or blue light. In addition, the size of the quantum dots may be adjusted such that light of various suitable colors are combined to emit white light.

Electron Transport Region in Interlayer 130

The electron transport region may have: i) a single-layered structure including (e.g., consisting of) a single layer including (e.g., consisting of) a single material, ii) a single-layered structure including (e.g., consisting of) a single layer including (e.g., consisting of) a plurality of different materials, or iii) a multi-layered structure including a plurality of layers including different materials.

In some embodiments, the electron transport region may include a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

For example, the electron transport region may have an electron transport layer/electron injection layer structure or a hole blocking layer/electron transport layer/electron injection layer structure, wherein, in each structure, layers are stacked sequentially on the emission layer.

The electron transport region (for example, the hole blocking layer or the electron transport layer in the electron transport region) may include a metal-free compound including at least one π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group.

In an embodiment, the electron transport region may include a compound represented by Formula 601:

[Ar₆₀₁]_(xe11)-[(L₆₀₁)_(xe1)-R₆₀₁]_(xe21)  Formula 601

wherein, in Formula 601,

Ar₆₀₁ and L₆₀₁ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a),

xe11 may be 1, 2, or 3,

xe1 may be 0, 1, 2, 3, 4, or 5,

R₆₀₁ may be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a), a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a), —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃), —C(═O)(Q₆₀₁), —S(═O)₂(Q₆₀₁), or —P(═O)(Q₆₀₁)(Q₆₀₂),

Q₆₀₁ to Q₆₀₃ may each be the same as described in connection with Q₁,

xe21 may be 1, 2, 3, 4, or 5, and

at least one of Arm, L₆₀₁, and R₆₀₁ may each independently be air electron-deficient nitrogen-containing C₁-C₆₀ cyclic group unsubstituted or substituted with at least one R_(10a).

In one or more embodiments, when xe11 in Formula 601 is 2 or more, two or more of Ar₆₀₁(s) may be linked to each other via a single bond.

In one or more embodiments, Ar₆₀₁ in Formula 601 may be a substituted or unsubstituted anthracene group.

In one or more embodiments, the electron transport region may include a compound represented by Formula 601-1:

wherein, in Formula 601-1,

X₆₁₄ may be N or C(R₆₁₄), X₆₁₅ may be N or C(R₆₁₅), X₆₁₆ may be N or C(R₆₁₆), and at least one of X₆₁₄ to X₆₁₆ may be N,

L₆₁₁ to L₆₁₃ may each be the same as described in connection with L₆₀₁,

xe611 to xe613 may each be the same as described in connection with xe1,

R₆₁₁ to R₆₁₃ may each be the same as described in connection with R₆₀₁, and

R₆₁₄ to R₆₁₆ may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a), or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a).

For example, xe1 and xe611 to xe613 in Formulae 601 and 601-1 may each independently be 0, 1, or 2.

The electron transport region may include one of Compounds ET1 to ET45, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), Alq₃, BAlq, TAZ, NTAZ, or any combination thereof:

A thickness of the electron transport region may be in a range of about 160 Å to about 5,000 Å, for example, about 100 Å to about 4,000 Å. When the electron transport region includes the hole blocking layer, the electron transport layer, or any combination thereof, a thickness of the hole blocking layer or a thickness of the electron transport layer may be in a range of about 20 Å to about 1,000 Å, for example, about 30 Å to about 300 Å, and a thickness of the electron transport layer may be in a range of about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. When the thickness of the hole blocking layer and/or the electron transport layer is within any of the ranges above, suitable or satisfactory electron transport characteristics may be obtained without a substantial increase in driving voltage.

The electron transport region (for example, the electron transport layer in the electron transport region) may further include, in addition to the materials described above, a metal-containing material.

The metal-containing material may include an alkali metal complex, an alkaline earth-metal complex, or any combination thereof. A metal ion of the alkali metal complex may be a Li ion, a Na ion, a K ion, a Rb ion, or a Cs ion, and a metal ion of the alkaline earth-metal complex may be a Be ion, a Mg ion, a Ca ion, a Sr ion, or a Ba ion. A ligand coordinated with the metal ion of the alkali metal complex or the alkaline earth-metal complex may be a hydroxy quinoline, a hydroxy isoquinoline, a hydroxy benzoquinoline, a hydroxy acridine, a hydroxy phenanthridine, a hydroxy phenyloxazole, a hydroxy phenylthiazole, a hydroxy diphenyloxadiazole, a hydroxy diphenylthiadiazole, a hydroxy phenylpyridine, a hydroxy phenylbenzimidazole, a hydroxy phenylbenzothiazole, a bipyridine, a phenanthroline, a cyclopentadiene, or any combination thereof.

For example, the metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (LiQ) or ET-D2:

The electron transport region may include an electron injection layer that facilitates the injection of electrons from the second electrode 150. The electron injection layer may directly contact (e.g., physically contact) the second electrode 150.

The electron injection layer may have: i) a single-layered structure including (e.g., consisting of) a single layer including (e.g., consisting of) a single material, ii) a single-layered structure including (e.g., consisting of) a single layer including (e.g., consisting of) a plurality of different materials, or iii) a multi-layered structure including a plurality of layers including different materials.

The electron injection layer may include an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal-containing compound, an alkaline earth metal-containing compound, a rare earth metal-containing compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combination thereof.

The alkali metal may include Li, Na, K, Rb, Cs, or any combination thereof. The alkaline earth metal may include Mg, Ca, Sr, Ba, or any combination thereof. The rare earth metal may include Sc, Y, Ce, Tb, Yb, Gd, or any combination thereof.

The alkali metal-containing compound, the alkaline earth metal-containing compound, and the rare earth metal-containing compound may be oxides and halides (for example, fluorides, chlorides, bromides, or iodides) of the alkali metal, the alkaline earth metal, and the rare earth metal, telluride, or any combination thereof.

The alkali metal-containing compound may be alkali metal oxides, such as Li₂O, Cs₂O, and/or K₂O, and alkali metal halides, such as LiF, NaF, CsF, KF, LiI, NaI, CsI, and/or KI, or any combination thereof. The alkaline earth metal-containing compound may include an alkaline earth metal compound, such as BaO, SrO, CaO, Ba_(x)Sr_(1-x)O (x is a real number that satisfies the condition of 0<x<1), and/or Ba_(x)Ca_(1-x)O (x is a real number that satisfies the condition of 0<x<1). The rare earth metal-containing compound may include YbF₃, ScF₃, Sc₂O₃, Y₂O₃, Ce₂O₃, GdF₃, TbF₃, YbI₃, ScI₃, TbI₃, or any combination thereof. In an embodiment, the rare earth metal-containing compound may include lanthanide metal telluride. Examples of the lanthanide metal telluride include LaTe, CeTe, PrTe, NdTe, PmTe, SmTe, EuTe, GdTe, TbTe, DyTe, HoTe, ErTe, TmTe, YbTe, LuTe, La₂Te₃, Ce₂Te₃, Pr₂Te₃, Nd₂Te₃, Pm₂Te₃, Sm₂Te₃, Eu₂Te₃, Gd₂Te₃, Tb₂Te₃, Dy₂Te₃, Ho₂Te₃, Er₂Te₃, Tm₂Te₃, Yb₂Te₃, and Lu₂Te₃.

The alkali metal complex, the alkaline earth-metal complex, and the rare earth metal complex may include i) one of ions of the alkali metal, the alkaline earth metal, and the rare earth metal and ii), as a ligand linked to the metal ion, for example, hydroxyquinoline, hydroxy isoquinoline, hydroxybenzoquinoline, hydroxyacridine, hydroxyphenanthridine, hydroxyphenyloxazole, hydroxyphenylthiazole, hydroxydiphenyloxadiazole, hydroxydiphenylthiadiazole, hydroxyphenylpyridine, hydroxyphenyl benzimidazole, hydroxyphenylbenzothiazole, bipyridine, phenanthroline, cyclopentadiene, or any combination thereof.

The electron injection layer may include (e.g., consist of) an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal-containing compound, an alkaline earth metal-containing compound, a rare earth metal-containing compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combination thereof, or may further include an organic material (for example, a compound represented by Formula 601).

In an embodiment, the electron injection layer may include (e.g., consist of) i) an alkali metal-containing compound (for example, an alkali metal halide), or ii) a) an alkali metal-containing compound (for example, an alkali metal halide); and b) alkali metal, alkaline earth metal, rare earth metal, or any combination thereof. In an embodiment, the electron injection layer may be a KI:Yb co-deposited layer and/or a RbI:Yb co-deposited layer.

When the electron injection layer further includes an organic material, an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal-containing compound, an alkaline earth metal-containing compound, a rare earth metal-containing compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combination thereof may be homogeneously or non-homogeneously dispersed in a matrix including the organic material.

A thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, for example, about 3 Å to about 90 Å. When the thickness of the electron injection layer is within any of the ranges above, suitable or satisfactory electron injection characteristics may be obtained without a substantial increase in driving voltage.

Second Electrode 150

The second electrode 150 is on the interlayer 130 having such a structure. The second electrode 150 may be a cathode, which is an electron injection electrode, and as the material for forming the second electrode 150, a metal, an alloy, an electrically conductive compound, or any combination thereof, each having a low work function, may be used.

The second electrode 150 may include lithium (Li), silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), ytterbium (Yb), silver-ytterbium (Ag—Yb), ITO, IZO, or any combination thereof. The second electrode 150 may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.

The second electrode 150 may have a single-layered structure or a multi-layered structure including two or more layers.

Capping Layer

A first capping layer may be outside the first electrode 110, and/or a second capping layer may be outside the second electrode 150. In more detail, the light-emitting device 10 may have a structure in which the first capping layer, the first electrode 110, the interlayer 130, and the second electrode 150 are sequentially stacked in this stated order, a structure in which the first electrode 110, the interlayer 130, the second electrode 150, and the second capping layer are sequentially stacked in this stated order, or a structure in which the first capping layer, the first electrode 110, the interlayer 130, the second electrode 150, and the second capping layer are sequentially stacked in this stated order.

Light generated in an emission layer of the interlayer 130 of the light-emitting device 10 may be extracted (e.g., irradiated) toward the outside through the first electrode 110, which is a semi-transmissive electrode or a transmissive electrode, and the first capping layer, and light generated in an emission layer of the interlayer 130 of the light-emitting device 10 may be extracted (e.g., irradiated) toward the outside through the second electrode 150, which is a semi-transmissive electrode or a transmissive electrode, and the second capping layer.

The first capping layer and the second capping layer may increase external luminescence efficiency according to the principle of constructive interference. Accordingly, the light extraction efficiency of the light-emitting device 10 is increased, so that the luminescence efficiency of the light-emitting device 10 may be improved.

Each of the first capping layer and the second capping layer may include a material having a refractive index of 1.6 or more (at a wavelength of 589 nm).

The first capping layer and the second capping layer may each independently be an organic capping layer including an organic material, an inorganic capping layer including an inorganic material, or a composite capping layer including an organic material and an inorganic material.

At least one selected from the first capping layer and the second capping layer may each independently include a carbocyclic compound, a heterocyclic compound, an amine group-containing compound, a porphyrine derivative, a phthalocyanine derivative, a naphthalocyanine derivative, an alkali metal complex, an alkaline earth-metal complex, or a combination thereof. The carbocyclic compound, the heterocyclic compound, and the amine group-containing compound may be optionally substituted with a substituent containing O, N, S, Se, Si, F, Cl, Br, I, or any combination thereof.

In an embodiment, at least one of the first capping layer and the second capping layer may each independently include an amine group-containing compound.

In an embodiment, at least one of the first capping layer and second capping layer may each independently include a compound represented by Formula 201, a compound represented by Formula 202, or any combination thereof.

In one or more embodiments, at least one of the first capping layer and the second capping layer may each independently include one of Compounds HT28 to HT33, one of Compounds CP1 to CP6, β-NPB, or any combination thereof:

Electronic Apparatus

The light-emitting device may be included in various suitable electronic apparatuses. For example, the electronic apparatus including the light-emitting device may be a light-emitting apparatus, an authentication apparatus, and/or the like.

The electronic apparatus (for example, light-emitting apparatus) may further include, in addition to the light-emitting device, i) a color filter, ii) a color conversion layer, or iii) a color filter and a color conversion layer. The color filter and/or the color conversion layer may be in at least one traveling direction of light emitted from the light-emitting device. For example, light emitted from the light-emitting device may be blue light or white light. The light-emitting device may be the same as described above. In an embodiment, the color conversion layer may include quantum dots. The quantum dot may be, for example, a quantum dot as described elsewhere herein.

The electronic apparatus may include a first substrate. The first substrate may include a plurality of subpixel areas, the color filter includes a plurality of color filter areas respectively corresponding to the plurality of subpixel areas, and the color conversion layer may include a plurality of color conversion areas respectively corresponding to the subpixel areas.

A pixel-defining film may be between the plurality of subpixel areas to define each of the subpixel areas.

The color filter may further include the color filter areas and a light-blocking pattern between adjacent color filter areas of the color filter areas, and the color conversion layer may further include the color conversion areas and a light-blocking pattern between adjacent color conversion areas of the color conversion areas.

The color filter areas (or the color conversion areas) may include a first area emitting first color light, a second area emitting second color light, and/or a third area emitting third color light, and the first color light, the second color light, and/or the third color light may have different maximum emission wavelengths from one another. For example, the first color light may be red light, the second color light may be green light, and the third color light may be blue light. For example, the color filter areas (or the color conversion areas) may include quantum dots. In more detail, the first area may include red quantum dots, the second area may include green quantum dots, and the third area may not include quantum dots. The quantum dot is the same as described elsewhere in the present specification. Each of the first area, the second area, and/or the third area may further include a scatterer.

In an embodiment, the light-emitting device may emit a first light, the first area may absorb the first light to emit a first first-color light, the second area may absorb the first light to emit a second first-color light, and the third area may absorb the first light to emit a third first-color light. In this embodiment, the first first-color light, the second first-color light, and the third first-color light may have different maximum luminescence wavelengths from one another. In more detail, the first light may be blue light, the first first-color light may be red light, the second first-color light may be green light, and the third first-color light may be blue light.

The electronic apparatus may further include a thin-film transistor in addition to the light-emitting device 10 as described above. The thin-film transistor may include a source electrode, a drain electrode, and an activation layer, wherein any one selected from the source electrode and the drain electrode may be in electrical connection with any one selected from the first electrode 110 and the second electrode 150 of the light-emitting device 10.

The thin-film transistor may further include a gate electrode, a gate insulation layer, and/or the like.

The active layer may include crystalline silicon, amorphous silicon, organic semiconductor, oxide semiconductor, and/or the like.

The electronic apparatus may further include a sealing portion for sealing the light-emitting device. The sealing portion may be between the light-emitting device and the color filter and/or between the light-emitting device and the color conversion layer. The sealing portion allows light from the light-emitting device 10 to be extracted to the outside, while concurrently (e.g., simultaneously) preventing or reducing penetration of ambient air and/or moisture into the light-emitting device 10. The sealing portion may be a sealing substrate including a transparent glass substrate or a plastic substrate. The sealing portion may be a thin-film encapsulation layer including at least one layer of an organic layer and/or an inorganic layer. When the sealing portion is a thin-film encapsulation layer, the electronic apparatus may be flexible.

On the sealing portion, in addition to the color filter and/or color conversion layer, various suitable functional layers may be further included according to the use of the electronic apparatus. The functional layers may include a touch screen layer, a polarization layer, and/or the like. The touch screen layer may be a pressure-sensitive touch screen layer, a capacitive touch screen layer, and/or an infrared touch screen layer. The authentication apparatus may be, for example, a biometric authentication apparatus for authenticating an individual by using biometric information of a biometric body (for example, a fingertip, a pupil, and/or the like).

The authentication apparatus may further include, in addition to the light-emitting device, a biometric information collector.

The electronic apparatus may be applied to various suitable displays, light sources, lighting, personal computers (for example, a mobile personal computer), mobile phones, digital cameras, electronic organizers, electronic dictionaries, electronic game machines, medical instruments (for example, electronic thermometers, sphygmomanometers, blood glucose meters, pulse measurement devices, pulse wave measurement devices, electrocardiogram displays, ultrasonic diagnostic devices, and/or endoscope displays), fish finders, various suitable measuring instruments, meters (for example, meters for a vehicle, an aircraft, and/or a vessel), projectors, and/or the like.

Description of FIGS. 2 and 3

FIG. 2 is a cross-sectional view showing a light-emitting apparatus according to an embodiment of the present disclosure.

The light-emitting apparatus of FIG. 2 includes a substrate 100, a thin-film transistor (TFT), a light-emitting device, and an encapsulation portion 300 that seals light-emitting device.

The substrate 100 may be a flexible substrate, a glass substrate, or a metal substrate. A buffer layer 210 may be on the substrate 100. The buffer layer 210 prevents or reduces the penetration of impurities through the substrate 100 and may provide a flat surface on the substrate 100.

A TFT may be on the buffer layer 210. The TFT may include an activation layer 220, a gate electrode 240, a source electrode 260, and a drain electrode 270.

The activation layer 220 may include an inorganic semiconductor such as silicon and/or polysilicon, an organic semiconductor, and/or an oxide semiconductor, and may include a source region, a drain region and a channel region.

A gate insulating film 230 for insulating the activation layer 220 from the gate electrode 240 may be on the activation layer 220, and the gate electrode 240 may be on the gate insulating film 230.

An interlayer insulating film 250 may be on the gate electrode 240. The interlayer insulating film 250 is between the gate electrode 240 and the source electrode 260 to insulate the gate electrode 240 from the source electrode 260 and between the gate electrode 240 and the drain electrode 270 to insulate the gate electrode 240 from the drain electrode 270.

The source electrode 260 and the drain electrode 270 may be on the interlayer insulating film 250. The interlayer insulating film 250 and the gate insulating film 230 may be formed to expose the source region and the drain region of the activation layer 220, and the source electrode 260 and the drain electrode 270 may be in contact (e.g., physical contact) with the exposed portions of the source region and the drain region of the activation layer 220.

The TFT may be electrically coupled to a light-emitting device to drive the light-emitting device, and is covered by a passivation layer 280. The passivation layer 280 may include an inorganic insulating film, an organic insulating film, or a combination thereof. A light-emitting device may be provided on the passivation layer 280. The light-emitting device includes the first electrode 110, the interlayer 130, and the second electrode 150.

The first electrode 110 may be on the passivation layer 280. The passivation layer 280 does not completely cover the drain electrode 270 and exposes a portion of the drain electrode 270, and the first electrode 110 may be coupled to the exposed portion of the drain electrode 270.

A pixel defining layer 290 including an insulating material may be on the first electrode 110. The pixel defining layer 290 may expose a certain region of the first electrode 110, and the interlayer 130 may be formed in the exposed region of the first electrode 110. The pixel defining layer 290 may be a polyimide or polyacryl-based organic film. In some embodiments, at least some layers of the interlayer 130 may extend beyond the upper portion of the pixel defining layer 290 and thus may be in the form of a common layer.

The second electrode 150 may be on the interlayer 130, and a capping layer 170 may be additionally formed on the second electrode 150. The capping layer 170 may be formed to cover the second electrode 150.

The encapsulation portion 300 may be on the capping layer 170. The encapsulation portion 300 may be on a light-emitting device and protects the light-emitting device from moisture and/or oxygen. The encapsulation portion 300 may include: an inorganic film including silicon nitride (SiNx), silicon oxide (SiOx), indium tin oxide, indium zinc oxide, or any combination thereof; an organic film including polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyethylene sulfonate, polyoxymethylene, polyarylate, hexamethyldisiloxane, an acrylic resin (for example, polymethyl methacrylate and/or polyacrylic acid), an epoxy-based resin (for example, aliphatic glycidyl ether (AGE), or any combination thereof; or a combination of the inorganic film and the organic film.

FIG. 3 is a cross-sectional view showing a light-emitting apparatus according to another embodiment of the present disclosure.

The light-emitting apparatus of FIG. 3 is the same as the light-emitting apparatus of FIG. 2, except that a light-blocking pattern 500 and a functional region 400 are additionally on the encapsulation portion 300. The functional region 400 may be i) a color filter area, ii) a color conversion area, or iii) a combination of the color filter area and the color conversion area. In an embodiment, the light-emitting device included in the light-emitting apparatus of FIG. 3 may be a tandem light-emitting device.

Preparation Method

Layers constituting the hole transport region, an emission layer, and layers constituting the electron transport region may be formed in a certain region by using one or more suitable methods selected from vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) deposition, ink-jet printing, laser-printing, and laser-induced thermal imaging.

When layers constituting the hole transport region, the emission layer, and layers constituting the electron transport region are formed by vacuum deposition, the deposition may be performed at a deposition temperature in a range of about 100° C. to about 500° C., a vacuum degree in a range of about 10⁻⁸ torr to about 10⁻³ torr, and a deposition speed in a range of about 0.01 Å/sec to about 100 Å/sec by taking into account a composition of a material to be included in a layer to be formed and the structure of a layer to be formed.

When layers constituting the hole transport region, an emission layer, and layers constituting the electron transport region are formed by spin coating, the spin coating may be performed at a coating speed in a range of about 2,000 rpm to about 5,000 rpm and at a heat treatment temperature in a range of about 80° C. to 200° C. by taking into account a composition of a material to be included in a layer to be formed and the structure of a layer to be formed.

General Definition of at Least Some of the Substituents

The term “C₃-C₆₀ carbocyclic group,” as used herein, refers to a cyclic group that consists of carbon only and has three to sixty carbon atoms, and the term “C₁-C₆₀ heterocyclic group,” as used herein, refers to a cyclic group that has one to sixty carbon atoms and further includes, in addition to carbon, a heteroatom. The C₃-C₆₀ carbocyclic group and the C₁-C₆₀ heterocyclic group may each be a monocyclic group that consists of one ring or a polycyclic group in which two or more rings are condensed with each other (e.g., combined together with each other). In an embodiment, the number of ring-forming atoms of the C₁-C₆₀ heterocyclic group may be from 3 to 61.

The term “cyclic group,” as used herein, includes the C₃-C₆₀ carbocyclic group and the C₁-C₆₀ heterocyclic group.

The term “π electron-rich C₃-C₆₀ cyclic group,” as used herein, refers to a cyclic group that has three to sixty carbon atoms and does not include *—N=*′ as a ring-forming moiety, and the term “π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group,” as used herein, refers to a heterocyclic group that has one to sixty carbon atoms and includes *—N=*′ as a ring-forming moiety.

For example,

the C₃-C₆₀ carbocyclic group may be i) a group T1 or ii) a condensed cyclic group in which two or more groups T1 are condensed with (e.g., combined together with) each other (for example, a cyclopentadiene group, an adamantane group, a norbornane group, a benzene group, a pentalene group, a naphthalene group, an azulene group, an indacene group, acenaphthylene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a perylene group, a pentaphene group, a heptalene group, a naphthacene group, a picene group, a hexacene group, a pentacene group, a rubicene group, a coronene group, an ovalene group, an indene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, an indenophenanthrene group, or an indenoanthracene group),

the C₁-C₆₀ heterocyclic group may be i) a group T2, ii) a condensed cyclic group in which two or more groups T2 are condensed with each other (e.g., combined together with each other), or iii) a condensed cyclic group in which at least one group T2 and at least one group T1 are condensed with (e.g., combined together with) each other (for example, a pyrrole group, a thiophene group, a furan group, an indole group, a benzoindole group, a naphthoindole group, an isoindole group, a benzoisoindole group, a naphthoisoindole group, a benzosilole group, a benzothiophene group, a benzofuran group, a carbazole group, a dibenzosilole group, a dibenzothiophene group, a dibenzofuran group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, a benzosilolocarbazole group, a benzoindolocarbazole group, a benzocarbazole group, a benzonaphthofuran group, a benzonaphthothiophene group, a benzonaphthosilole group, a benzofurodibenzofuran group, a benzofurodibenzothiophene group, a benzothieno dibenzothiophene group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzoisoxazole group, a benzothiazole group, a benzoisothiazole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a benzoisoquinoline group, a quinoxaline group, a benzoquinoxaline group, a quinazoline group, a benzoquinazoline group, a phenanthroline group, a cinnoline group, a phthalazine group, a naphthyridine group, an imidazopyridine group, an imidazopyrimidine group, an imidazotriazine group, an imidazopyrazine group, an imidazopyridazine group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, an azadibenzothiophene group, or an azadibenzofuran group),

the π electron-rich C₃-C₆₀ cyclic group may be i) a group T1, ii) a condensed cyclic group in which two or more groups T1 are condensed with each other (e.g., combined together with each other), iii) a group T3, iv) a condensed cyclic group in which two or more groups T3 are condensed with each other (e.g., combined together with each other), or v) a condensed cyclic group in which at least one group T3 and at least one group T1 are condensed with (e.g., combined together with) each other (for example, a C₃-C₆₀ carbocyclic group, a pyrrole group, a thiophene group, a furan group, an indole group, a benzoindole group, a naphthoindole group, an isoindole group, a benzoisoindole group, a naphthoisoindole group, a benzosilole group, a benzothiophene group, a benzofuran group, a carbazole group, a dibenzosilole group, a dibenzothiophene group, a dibenzofuran group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, a benzosilolocarbazole group, a benzoindolocarbazole group, a benzocarbazole group, a benzonaphthofuran group, a benzonaphthothiophene group, a benzonaphthosilole group, a benzofurodibenzofuran group, a benzofurodibenzothiophene group, or a benzothienodibenzothiophene group),

the π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group may be i) a group T4, ii) a condensed cyclic group in which two or more groups T4 are condensed with each other (e.g., combined together with each other), iii) a condensed cyclic group in which at least one group T4 and at least one group T1 are condensed with each other (e.g., combined together with each other), iv) a condensed cyclic group in which at least one group T4 and at least one group T3 are condensed with each other (e.g., combined together with each other), or v) a condensed cyclic group in which at least one group T4, at least one group T1, and at least one group T3 are condensed with (e.g., combined together with) each other (for example, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzoisoxazole group, a benzothiazole group, a benzoisothiazole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a benzoisoquinoline group, a quinoxaline group, a benzoquinoxaline group, a quinazoline group, a benzoquinazoline group, a phenanthroline group, a cinnoline group, a phthalazine group, a naphthyridine group, an imidazopyridine group, an imidazopyrimidine group, an imidazotriazine group, an imidazopyrazine group, an imidazopyridazine group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, an azadibenzothiophene group, or an azadibenzofuran group),

the group T1 may be a cyclopropane group, a cyclobutane group, a cyclopentane group, a cyclohexane group, a cycloheptane group, a cyclooctane group, a cyclobutene group, a cyclopentene group, a cyclopentadiene group, a cyclohexene group, a cyclohexadiene group, a cycloheptene group, an adamantane group, a norbornane group (or, a bicyclo[2.2.1]heptane group), a norbornene group, a bicyclo[1.1.1]pentane group, a bicyclo[2.1.1]hexane group, a bicyclo[2.2.2]octane group, or a benzene group,

the group T2 may be a furan group, a thiophene group, a 1H-pyrrole group, a silole group, a borole group, a 2H-pyrrole group, a 3H-pyrrole group, an imidazole group, a pyrazole group, a triazole group, a tetrazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, an azasilole group, an azaborole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, or a tetrazine group,

the group T3 may be a furan group, a thiophene group, a 1H-pyrrole group, a silole group, or a borole group,

the group T4 may be a 2H-pyrrole group, a 3H-pyrrole group, an imidazole group, a pyrazole group, a triazole group, a tetrazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, an azasilole group, an azaborole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, or a tetrazine group.

The terms “the cyclic group,” “the C₃-C₆₀ carbocyclic group,” “the C₁-C₆₀ heterocyclic group,” “the π electron-rich C₃-C₆₀ cyclic group,” or “the π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group,” as used herein, refer to a group that is condensed with (e.g., combined together with) a cyclic group, a monovalent group, a polyvalent group (for example, a divalent group, a trivalent group, a tetravalent group, and/or the like), according to the structure of a formula described with corresponding terms. In an embodiment, “a benzene group” may be a benzo group, a phenyl group, a phenylene group, and/or the like, which may be easily understand by one of ordinary skill in the art according to the structure of a formula including the “benzene group.”

In an embodiment, examples of the monovalent C₃-C₆₀ carbocyclic group and the monovalent C₁-C₆₀ heterocyclic group include a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, and examples of the divalent C₃-C₆₀ carbocyclic group and the monovalent C₁-C₆₀ heterocyclic group include a C₃-C₁₀ cycloalkylene group, a C₁-C₁₀ heterocycloalkylene group, a C₃-C₁₀ cycloalkenylene group, a C₁-C₁₀ heterocycloalkenylene group, a C₆-C₆₀ arylene group, a C₁-C₆₀ heteroarylene group, a divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group.

The term “C₁-C₆₀ alkyl group,” as used herein, refers to a linear or branched aliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, a neopentyl group, an isopentyl group, a sec-pentyl group, a 3-pentyl group, a sec-isopentyl group, an n-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptyl group, an n-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group, an n-decyl group, an isodecyl group, a sec-decyl group, and a tert-decyl group. The term “C₁-C₆₀ alkylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₁-C₆₀ alkyl group.

The term “C₂-C₆₀ alkenyl group,” as used herein, refers to a monovalent hydrocarbon group having at least one carbon-carbon double bond at a main chain (e.g., in the middle) or at a terminal end (e.g., the terminus) of a C₂-C₆₀ alkyl group, and examples thereof include an ethenyl group, a propenyl group, and a butenyl group. The term “C₂-C₆₀ alkenylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group,” as used herein, refers to a monovalent hydrocarbon group having at least one carbon-carbon triple bond at a main chain (e.g., in the middle) or at a terminal end (e.g., the terminus) of a C₂-C₆₀ alkyl group, and examples thereof include an ethynyl group, and a propynyl group. The term “C₂-C₆₀ alkynylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₂-C₆₀ alkynyl group.

The term “C₁-C₆₀ alkoxy group,” as used herein, refers to a monovalent group represented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group), and examples thereof include a methoxy group, an ethoxy group, and an isopropyloxy group.

The term “C₃-C₁₀ cycloalkyl group,” as used herein, refers to a monovalent saturated hydrocarbon cyclic group having 3 to 10 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cycloctyl group, an adamantanyl group, a norbornanyl group (or a bicyclo[2.2.1]heptyl group), a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, and a bicyclo[2.2.2]octyl group. The term “C₃-C₁₀ cycloalkylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group,” as used herein, refers to a monovalent cyclic group that further includes, in addition to a carbon atom, at least one heteroatom as a ring-forming atom and has 1 to 10 carbon atoms, and examples thereof include a 1,2,3,4-oxatriazolidinyl group, a tetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₁-C₁₀ heterocycloalkyl group.

The term “C₃-C₁₀ cycloalkenyl group,” as used herein, refers to a monovalent cyclic group that has 3 to 10 carbon atoms and at least one carbon-carbon double bond in the ring thereof and no aromaticity (e.g., is not aromatic), and non-limiting examples thereof include a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The term “C₃-C₁₀ cycloalkenylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group,” as used herein, refers to a monovalent cyclic group that has, in addition to a carbon atom, at least one heteroatom as a ring-forming atom, 1 to 10 carbon atoms, and at least one carbon-carbon double bond in the cyclic structure thereof. Examples of the C₁-C₁₀ heterocycloalkenyl group include a 4,5-dihydro-1,2,3,4-oxatriazolylgroup, a 2,3-dihydrofuranyl group, and a 2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group,” as used herein, refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and the term “C₆-C₆₀ arylene group,” as used herein, refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Examples of the C₆-C₆₀ aryl group include a phenyl group, a pentalenyl group, a naphthyl group, an azulenyl group, an indacenyl group, an acenaphthyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a heptalenyl group, a naphthacenyl group, a picenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, and an ovalenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀ arylene group each include two or more rings, the two or more rings may be condensed to each other.

The term “C₁-C₆₀ heteroaryl group,” as used herein, refers to a monovalent group having a heterocyclic aromatic system that has, in addition to a carbon atom, at least one heteroatom as a ring-forming atom, and 1 to 60 carbon atoms. The term “C₁-C₆₀ heteroarylene group,” as used herein, refers to a divalent group having a heterocyclic aromatic system that has, in addition to a carbon atom, at least one heteroatom as a ring-forming atom, and 1 to 60 carbon atoms. Examples of the C₁-C₆₀ heteroaryl group include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, a benzoquinolinyl group, an isoquinolinyl group, a benzoisoquinolinyl group, a quinoxalinyl group, a benzoquinoxalinyl group, a quinazolinyl group, a benzoquinazolinyl group, a cinnolinyl group, a phenanthrolinyl group, a phthalazinyl group, and a naphthyridinyl group. When the C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group each include two or more rings, the two or more rings may be condensed with each other (e.g., combined together with each other).

The term “monovalent non-aromatic condensed polycyclic group,” as used herein, refers to a monovalent group (for example, having 8 to 60 carbon atoms) having two or more rings condensed with each other (e.g., combined together with each other), only carbon atoms as ring-forming atoms, and no aromaticity in its entire molecular structure (e.g., is not aromatic when considered as a whole). Examples of the monovalent non-aromatic condensed polycyclic group include an indenyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, an indenophenanthrenyl group, and an indenoanthracenyl group. The term “divalent non-aromatic condensed polycyclic group,” as used herein, refers to a divalent group having substantially the same structure as the monovalent non-aromatic condensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group,” as used herein, refers to a monovalent group (for example, having 1 to 60 carbon atoms) having two or more rings condensed to each other (e.g., combined together with each other), at least one heteroatom other than carbon atoms, as a ring-forming atom, and no aromaticity in its entire molecular structure (e.g., is not aromatic when considered as a whole). Examples of the monovalent non-aromatic condensed heteropolycyclic group include a pyrrolyl group, a thiophenyl group, a furanyl group, an indolyl group, a benzoindolyl group, a naphthoindolyl group, an isoindolyl group, a benzoisoindolyl group, a naphthoisoindolyl group, a benzosilolyl group, a benzothiophenyl group, a benzofuranyl group, a carbazolyl group, a dibenzosilolyl group, a dibenzothiophenyl group, a dibenzofuranyl group, an azacarbazolyl group, an azafluorenyl group, an azadibenzosilolyl group, an azadibenzothiophenyl group, an azadibenzofuranyl group, a pyrazolyl group, an imidazolyl group, a triazolyl group, a tetrazolyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, an oxadiazolyl group, a thiadiazolyl group, a benzopyrazolyl group, a benzimidazolyl group, a benzoxazolyl group, a benzothiazolyl group, a benzoxadiazolyl group, a benzothiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an imidazotriazinyl group, an imidazopyrazinyl group, an imidazopyridazinyl group, an indenocarbazolyl group, an indolocarbazolyl group, a benzofurocarbazolyl group, a benzothienocarbazolyl group, a benzosilolocarbazolyl group, a benzoindolocarbazolyl group, a benzocarbazolyl group, a benzonaphthofuranyl group, a benzonaphthothiophenyl group, a benzonaphthosilolyl group, a benzofurodibenzofuranyl group, a benzofurodibenzothiophenyl group, and a benzothienodibenzothiophenyl group. The term “divalent non-aromatic condensed heteropolycyclic group,” as used herein, refers to a divalent group having substantially the same structure as the monovalent non-aromatic condensed heteropolycyclic group.

The term “C₆-C₆₀ aryloxy group,” as used herein, refers to —OA₁₀₂ (wherein A₁₀₂ is the C₆-C₆₀ aryl group), and the term “C₆-C₆₀ arylthio group,” as used herein refers to —SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group).

The term “R_(10a),” as used herein, refers to:

deuterium (-D), —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, or a nitro group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀ alkoxy group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁₁), —P(═O)(Q₁₁)(Q₁₂), or any combination thereof;

a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, or a C₆-C₆₀ arylthio group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), —P(═O)(Q₂₁)(Q₂₂), or any combination thereof; or

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), or —P(═O)(Q₃₁)(Q₃₂).

Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃ and Q₃₁ to Q₃₃, as described herein, may each independently be: hydrogen; deuterium; —F; —Cl; —Br; —I; a hydroxyl group; a cyano group; a nitro group; a C₁-C₆₀ alkyl group; a C₂-C₆₀ alkenyl group; a C₂-C₆₀ alkynyl group; a C₁-C₆₀ alkoxy group; or a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group, each unsubstituted or substituted with deuterium, —F, a cyano group, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a biphenyl group, or any combination thereof.

The term “hetero atom,” as used herein, refers to any atom other than a carbon atom. Examples of the heteroatom include O, S, N, P, Si, B, Ge, Se, and any combination thereof.

The term “Ph,” as used herein, refers to a phenyl group, the term “Me,” as used herein, refers to a methyl group, the term “Et,” as used herein, refers to an ethyl group, the term “ter-Bu” or “But,” as used herein, refers to a tert-butyl group, and the term “OMe,” as used herein, refers to a methoxy group.

The term “biphenyl group,” as used herein, refers to “a phenyl group substituted with a phenyl group.” In other words, the “biphenyl group” is a substituted phenyl group having a C₆-C₆₀ aryl group as a substituent.

The term “terphenyl group,” as used herein, refers to “a phenyl group substituted with a biphenyl group.” In other words, the “terphenyl group” is a substituted phenyl group having, as a substituent, a C₆-C₆₀ aryl group substituted with a C₆-C₆₀ aryl group.

* and *′, as used herein, unless defined otherwise, each refer to a binding site to a neighboring atom in a corresponding formula.

Hereinafter, a compound according to embodiments and a light-emitting device according to embodiments will be described in more detail with reference to Synthesis Examples and Examples. The wording “B was used instead of A” used in describing Synthesis Examples refers to that an identical molar equivalent of B was used in place of A.

EXAMPLES Preparation of Host Preparation of Host-1

3 g (0.0097 mol) of N-(naphthalen-2-yl)dibenzo[b,d]furan-4-amine was dissolved in 100 mL of 2-Me-THF in a 3-neck flask, and a 1.5 M (2-Me-THF solvent) butylmagnesium chloride solution was added thereto to form a mixed solution. The mixed solution was stirred at room temperature for 3 hours.

Then, 1.39 g (0.0039 mol) of 1,6-dibromopyrene was added to the 3-neck flask, followed by being stirred at a temperature of 185° C. for 72 hours. Next, the reaction was terminated using water, an extraction process using methylene chloride (MC) was performed three times, and the solvent was removed therefrom. The resultant product thus obtained was subjected to column chromatography using a solvent, e.g., ethyl acetate (EA):hexane (Hex) (1:10), so as to obtain 1.72 g (yield: 54%) of Host-1 compound.

H-NMR (CDCl₃): 7.98-7.92 (6H, m), 7.78-7.28 (26H, m), 7.11 (2H, t), 6.97 (2H, d)

Preparation of Host-2

In a nitrogen atmosphere, 11-bromonaphtho[2,1-b]benzofuran (3 g, 0.0101 mol) and (3-(tert-butyl)-10-phenylanthracen-9-yl)boronic acid (4.65 g, 0.01313 mmol) were completely dissolved in 300 mL of toluene in 500 mL round-bottom flask, and a 2M potassium carbonate aqueous solution (150 mL) was slowly added thereto. Then, tetrakis-(triphenylphosphine)palladium (0.47 g, 0.0004 mmol) was added thereto, and heated and stirred for 4 hours. After the reaction temperature was lowered to room temperature, a water layer was removed therefrom, and the resultant product was dried with anhydrous magnesium sulfate, and subjected to column chromatography using a solvent, e.g., EA:Hex (1:10), so as to obtain 2.02 g (yield: 38%) of Host-2 compound.

H-NMR (DMSO): 8.54 (1H, d), 8.23 (2H, m), 7.99 (2H, d), 7.82 (1H, d), 7.69-7.27 (15H, m), 1.49 (9H, s)

Manufacture of Light-Emitting Device Comparative Example 1

An ITO 300 Δ/Ag 50 Δ/ITO 300 Å glass substrate (anode) was cut to a size of 50 mm×50 mm×0.7 mm, sonicated with isopropyl alcohol and pure water each for 15 minutes, and then cleaned by exposure to ultraviolet rays and ozone for 30 minutes. Then, the glass substrate was provided to a vacuum deposition apparatus.

HATCN was vacuum-deposited on the glass substrate to form a hole injection layer having a thickness of 50 Å. Next, NPB as a hole-transporting compound was vacuum-deposited on the hole injection layer to form a hole transport layer having a thickness of 600 Å.

Compound TCTA was vacuum-deposited on the hole transport layer to form an electron blocking layer having a thickness of 50 Å.

Compound 100 (host) and Compound 200 (dopant) were co-deposited to a weight ratio of 97:3 on the electron blocking layer to form a first emission layer having a thickness of 100 Å. Host-2 (host) and Compound 200 (dopant) were co-deposited to a weight ratio of 97:3 on the first emission layer to form a second emission layer having a thickness of 100 Å.

Subsequently, T2T was formed on the second emission layer to form a hole blocking layer having a thickness of 50 Å, and TPM-TAZ and Liq were deposited on to a weight ratio 5:5 to form an electron transport layer having a thickness of 300 Å.

Yb was vacuum-deposited on the electron transport layer to a thickness of 10 Å, AgMg was then vacuum deposited thereon to form a cathode having a thickness of 120 Å, and CPL was deposited on the cathode to form a capping layer having a thickness of 600 Å, thereby completing the manufacture of a light-emitting device.

Comparative Example 2

A light-emitting device was manufactured in substantially the same manner as in Comparative Example 1, except that, in forming emission layers, Host-2 (host) and Compound 200 (dopant) were co-deposited to a weight ratio of 97:3 to form a first emission layer having a thickness of 100 Å, and Host-1 (host) and Compound 200 (dopant) were co-deposited to a weight ratio of 97:3 on the first emission layer to form a second emission layer having a thickness of 100 Å.

Example 1

A light-emitting device was manufactured in substantially the same manner as in Comparative Example 1, except that, in forming emission layers, Host-1 (host) and Compound 200 (dopant) were co-deposited to a weight ratio of 97:3 to form a first emission layer having a thickness of 100 Å, and Host-2 (host) and Compound 200 (dopant) were co-deposited to a weight ratio of 97:3 on the first emission layer to form a second emission layer having a thickness of 100 Å.

Example 2

A light-emitting device was manufactured in substantially the same manner as in Comparative Example 1, except that, in forming emission layers, Host-1 (host) and Compound 200 (dopant) were co-deposited to a weight ratio of 97:3 to form a first emission layer having a thickness of 100 Å, and Compound 100 (host) and Compound 200 (dopant) were co-deposited to a weight ratio of 97:3 on the first emission layer to form a second emission layer having a thickness of 100 Å.

T1 Energy Level Simulation

The T1 energy of Compound 100, Host-1, and Host-2, were simulated (or calculated) using the Gaussian program ([structure optimization] #B3LYP/6-31G*, [TD DFT] #B3LYP/6-31G* TD=(50-50, N states=3)) available from Gaussian Inc. The results are shown in Table 1.

TABLE 1 Compound T1 (eV) 100 1.78 Host-1 2.02 Host-2 1.75

To evaluate characteristics of the light-emitting devices manufactured according to Comparative Examples 1 and 2 and Examples 1 and 2, the driving voltage, efficiency, lifespan, and the like were measured at current density of 10 mA/cm².

Here, the driving voltage and current density of the light-emitting devices were measured using a source meter (Keithley Instrument, 2400 series), and the efficiency was measured using a measurement device C9920-2-12 of Hamamatsu Photonics Inc.

TABLE 2 Host in first Host in second Driving emission emission Voltage Efficiency Lifespan Luminance layer layer (V) (Cd/A) (T₉₇) (nit) Comparative Compound Host-2 3.7 6.1 80 1500 Example 1 100 Comparative Host-2 Host-1 3.6 6.0 77 1500 Example 2 Example 1 Host-1 Host-2 3.5 6.7 110 1500 Example 2 Host-1 Compound 3.6 6.5 105 1500 100

Referring to Table 2, it can be seen that the light-emitting devices manufactured according to Examples 1 and 2 showed excellent results in terms of efficiency and lifespan, compared to those of the light-emitting devices manufactured according to Comparative Examples 1 and 2.

According to the one or more embodiments, a light-emitting device shows a result of improving a lifespan compared to a device of the related art by preventing or reducing deterioration of an electron blocking layer.

It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the following claims, and equivalents thereof. 

What is claimed is:
 1. A light-emitting device comprising: a first electrode; a second electrode facing the first electrode, and an interlayer between the first electrode and the second electrode and comprising an emission layer, wherein the emission layer comprises a first emission layer comprising a first host and a second emission layer comprising a second host, and a triplet energy (T1_(H1)) of the first host and a triplet energy (T1_(H2)) of the second host satisfy Equation (1): T1_(H1) −T1_(H2)≥0.2 eV  (1).
 2. The light-emitting device of claim 1, wherein: the first electrode is an anode, the second electrode is a cathode, the interlayer further comprises a hole transport region between the first electrode and the emission layer and an electron transport region between the emission layer and the second electrode, the hole transport region comprises a hole injection layer, a hole transport layer, an emission auxiliary layer, an electron blocking layer, or any combination thereof, and the electron transport region comprises a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.
 3. The light-emitting device of claim 1, wherein each of the first emission layer and the second emission layer comprises a dopant, and the dopant of the first emission layer and the dopant of the second emission layer are the same compounds.
 4. The light-emitting device of claim 1, wherein the first emission layer and the second emission layer are in contact with each other.
 5. The light-emitting device of claim 1, wherein the emission layer emits blue light.
 6. The light-emitting device of claim 1, wherein the emission layer is a fluorescent emission layer.
 7. The light-emitting device of claim 1, wherein the interlayer further comprises a hole transport layer and an electron blocking layer that are between the first electrode and the emission layer, and the first emission layer and the electron blocking layer are in contact with each other.
 8. The light-emitting device of claim 1, wherein: the interlayer further comprises an electron transport layer and a hole blocking layer that are between the second electrode and the emission layer, and the second emission layer and the hole blocking layer are in contact with each other.
 9. The light-emitting device of claim 1, wherein: the first electrode is an anode, the second electrode is a cathode, the first emission layer and the second emission layer are in contact with each other, and holes provided from the first electrode and electrons provided from the second electrode recombine at an interface between the first emission layer and the second emission layer.
 10. The light-emitting device of claim 1, wherein the first host is a pyrene derivative compound.
 11. The light-emitting device of claim 10, wherein the first host is a symmetrical pyrene derivative compound.
 12. The light-emitting device of claim 1, wherein the second host is an anthracene derivative compound.
 13. The light-emitting device of claim 1, wherein the first host comprises any one of the following compounds:


14. The light-emitting device of claim 1, wherein the second host comprises any one of the following compounds:


15. The light-emitting device of claim 1, further comprising a capping layer.
 16. The light-emitting device of claim 15, wherein the capping layer is outside the first electrode and/or outside the second electrode.
 17. The light-emitting device of claim 15, wherein the capping layer has a refractive index in a range of 1.5 to 2.0 at a wavelength of 589 nm.
 18. An electronic apparatus comprising the light-emitting device of claim
 1. 19. The electronic apparatus of claim 18, further comprising a thin-film transistor, wherein the thin-film transistor comprises a source electrode and a drain electrode, and the first electrode of the light-emitting device is electrically coupled with one of the source electrode and the drain electrode of the thin-film transistor.
 20. The electronic apparatus of claim 19, further comprising quantum dots. 